/**
 * 提取自 watermark-dom
 * https://github.com/saucxs/watermark-dom
 */

var watermark = {}

var forceRemove = false

var defaultSettings = {
    watermark_id: 'wm_div_id', // 水印总体的id
    watermark_prefix: 'mask_div_id', // 小水印的id前缀
    watermark_txt: '测试水印', // 水印的内容
    watermark_x: 20, // 水印起始位置x轴坐标
    watermark_y: 20, // 水印起始位置Y轴坐标
    watermark_rows: 0, // 水印行数
    watermark_cols: 0, // 水印列数
    watermark_x_space: 50, // 水印x轴间隔
    watermark_y_space: 50, // 水印y轴间隔
    watermark_font: '微软雅黑', // 水印字体
    watermark_color: 'black', // 水印字体颜色
    watermark_fontsize: '18px', // 水印字体大小
    watermark_alpha: 0.15, // 水印透明度，要求设置在大于等于0.005
    watermark_width: 100, // 水印宽度
    watermark_height: 100, // 水印长度
    watermark_angle: 15, // 水印倾斜度数
    watermark_parent_width: 0, // 水印的总体宽度（默认值：body的scrollWidth和clientWidth的较大值）
    watermark_parent_height: 0, // 水印的总体高度（默认值：body的scrollHeight和clientHeight的较大值）
    watermark_parent_node: null, // 水印插件挂载的父元素element,不输入则默认挂在body上
    monitor: true // monitor 是否监控， true: 不可删除水印; false: 可删水印。
}

const MutationObserver = window.MutationObserver || window.WebKitMutationObserver || window.MozMutationObserver

// 监听dom是否被移除或者改变属性的回调函数
var domChangeCallback = function(records) {
    if (forceRemove) {
        forceRemove = false
        return
    }
    if (
        (globalSetting && records.length === 1) ||
         (records.length === 1 && records[0].removedNodes.length >= 1)
    ) {
        loadMark(globalSetting)
    }
}

var hasObserver = MutationObserver !== undefined
var watermarkDom = hasObserver
    ? new MutationObserver(domChangeCallback)
    : null
var option = {
    childList: true,
    attributes: true,
    subtree: true
}

/* 加载水印*/
var loadMark = function(settings) {
    /* 采用配置项替换默认值，作用类似jquery.extend*/
    if (arguments.length === 1 && typeof arguments[0] === 'object') {
        var src = arguments[0] || {}
        for (let key in src) {
            if (src[key] && defaultSettings[key] && src[key] === defaultSettings[key]) {
                continue
            } else if (src[key] || src[key] === 0) {
                /* veronic: resolution of watermark_angle=0 not in force*/
                defaultSettings[key] = src[key]
            }
        }
    }

    /* 如果元素存在则移除*/
    var watermark_element = document.getElementById(
        defaultSettings.watermark_id
    )
    watermark_element &&
         watermark_element.parentNode &&
         watermark_element.parentNode.removeChild(watermark_element)

    /* 如果设置水印挂载的父元素的id*/
    var watermark_parent_element = document.getElementById(
        defaultSettings.watermark_parent_node
    )
    var watermark_hook_element = watermark_parent_element || document.body

    /* 获取页面宽度*/
    var page_width = Math.max(watermark_hook_element.scrollWidth, watermark_hook_element.clientWidth)
    /* 获取页面最大长度*/
    var page_height = Math.max(watermark_hook_element.scrollHeight, watermark_hook_element.clientHeight)

    var setting = arguments[0] || {}
    var parentEle = watermark_hook_element

    var page_offsetTop = 0
    var page_offsetLeft = 0
    if (setting.watermark_parent_width || setting.watermark_parent_height) {
        /* 指定父元素同时指定了宽或高*/
        if (parentEle) {
            page_offsetTop = parentEle.offsetTop || 0
            page_offsetLeft = parentEle.offsetLeft || 0
            defaultSettings.watermark_x = defaultSettings.watermark_x + page_offsetLeft
            defaultSettings.watermark_y = defaultSettings.watermark_y + page_offsetTop
        }
    } else {
        if (parentEle) {
            page_offsetTop = parentEle.offsetTop || 0
            page_offsetLeft = parentEle.offsetLeft || 0
        }
    }

    /* 创建水印外壳div*/
    var otdiv = document.getElementById(defaultSettings.watermark_id)
    var shadowRoot = null

    if (!otdiv) {
        otdiv = document.createElement('div')
        /* 创建shadow dom*/
        otdiv.id = defaultSettings.watermark_id
        otdiv.setAttribute('style', 'pointer-events: none !important; display: block !important')
        /* 判断浏览器是否支持attachShadow方法*/
        if (typeof otdiv.attachShadow === 'function') {
            /* createShadowRoot Deprecated. Not for use in new websites. Use attachShadow*/
            shadowRoot = otdiv.attachShadow({ mode: 'open' })
        } else {
            shadowRoot = otdiv
        }
        /* 将shadow dom随机插入body内的任意位置*/
        var nodeList = watermark_hook_element.children
        var index = Math.floor(Math.random() * (nodeList.length - 1))
        if (nodeList[index]) {
            watermark_hook_element.insertBefore(otdiv, nodeList[index])
        } else {
            watermark_hook_element.appendChild(otdiv)
        }
    } else if (otdiv.shadowRoot) {
        shadowRoot = otdiv.shadowRoot
    }
    /* 三种情况下会重新计算水印列数和x方向水印间隔：1、水印列数设置为0，2、水印宽度大于页面宽度，3、水印宽度小于于页面宽度*/
    defaultSettings.watermark_cols = parseInt((page_width - defaultSettings.watermark_x) / (defaultSettings.watermark_width + defaultSettings.watermark_x_space))
    var temp_watermark_x_space = parseInt((page_width - defaultSettings.watermark_x - defaultSettings.watermark_width * defaultSettings.watermark_cols) / (defaultSettings.watermark_cols))
    defaultSettings.watermark_x_space = temp_watermark_x_space ? defaultSettings.watermark_x_space : temp_watermark_x_space
    var allWatermarkWidth

    /* 三种情况下会重新计算水印行数和y方向水印间隔：1、水印行数设置为0，2、水印长度大于页面长度，3、水印长度小于于页面长度*/
    defaultSettings.watermark_rows = parseInt((page_height - defaultSettings.watermark_y) / (defaultSettings.watermark_height + defaultSettings.watermark_y_space))
    var temp_watermark_y_space = parseInt((page_height - defaultSettings.watermark_y - defaultSettings.watermark_height * defaultSettings.watermark_rows) / (defaultSettings.watermark_rows))
    defaultSettings.watermark_y_space = temp_watermark_y_space ? defaultSettings.watermark_y_space : temp_watermark_y_space
    var allWatermarkHeight

    if (watermark_parent_element) {
        allWatermarkWidth = defaultSettings.watermark_x + defaultSettings.watermark_width * defaultSettings.watermark_cols + defaultSettings.watermark_x_space * (defaultSettings.watermark_cols - 1)
        allWatermarkHeight = defaultSettings.watermark_y + defaultSettings.watermark_height * defaultSettings.watermark_rows + defaultSettings.watermark_y_space * (defaultSettings.watermark_rows - 1)
    } else {
        allWatermarkWidth = page_offsetLeft + defaultSettings.watermark_x + defaultSettings.watermark_width * defaultSettings.watermark_cols + defaultSettings.watermark_x_space * (defaultSettings.watermark_cols - 1)
        allWatermarkHeight = page_offsetTop + defaultSettings.watermark_y + defaultSettings.watermark_height * defaultSettings.watermark_rows + defaultSettings.watermark_y_space * (defaultSettings.watermark_rows - 1)
    }

    var x
    var y
    for (var i = 0; i < defaultSettings.watermark_rows; i++) {
        if (watermark_parent_element) {
            y = page_offsetTop + defaultSettings.watermark_y + (page_height - allWatermarkHeight) / 2 + (defaultSettings.watermark_y_space + defaultSettings.watermark_height) * i
        } else {
            y = defaultSettings.watermark_y + (page_height - allWatermarkHeight) / 2 + (defaultSettings.watermark_y_space + defaultSettings.watermark_height) * i
        }
        for (var j = 0; j < defaultSettings.watermark_cols; j++) {
            if (watermark_parent_element) {
                x = page_offsetLeft + defaultSettings.watermark_x + (page_width - allWatermarkWidth) / 2 + (defaultSettings.watermark_width + defaultSettings.watermark_x_space) * j
            } else {
                x = defaultSettings.watermark_x + (page_width - allWatermarkWidth) / 2 + (defaultSettings.watermark_width + defaultSettings.watermark_x_space) * j
            }
            var mask_div = document.createElement('div')
            var oText = document.createTextNode(defaultSettings.watermark_txt)
            mask_div.appendChild(oText)
            /* 设置水印相关属性start*/
            mask_div.id = defaultSettings.watermark_prefix + i + j
            /* 设置水印div倾斜显示*/
            mask_div.style.webkitTransform = 'rotate(-' + defaultSettings.watermark_angle + 'deg)'
            mask_div.style.MozTransform = 'rotate(-' + defaultSettings.watermark_angle + 'deg)'
            mask_div.style.msTransform = 'rotate(-' + defaultSettings.watermark_angle + 'deg)'
            mask_div.style.OTransform = 'rotate(-' + defaultSettings.watermark_angle + 'deg)'
            mask_div.style.transform = 'rotate(-' + defaultSettings.watermark_angle + 'deg)'
            mask_div.style.visibility = ''
            mask_div.style.position = 'absolute'
            /* 选不中*/
            mask_div.style.left = x + 'px'
            mask_div.style.top = y + 'px'
            mask_div.style.overflow = 'hidden'
            mask_div.style.zIndex = '9999999'
            mask_div.style.opacity = defaultSettings.watermark_alpha
            mask_div.style.fontSize = defaultSettings.watermark_fontsize
            mask_div.style.fontFamily = defaultSettings.watermark_font
            mask_div.style.color = defaultSettings.watermark_color
            mask_div.style.textAlign = 'center'
            mask_div.style.width = defaultSettings.watermark_width + 'px'
            mask_div.style.height = defaultSettings.watermark_height + 'px'
            mask_div.style.display = 'block'
            mask_div.style['-ms-user-select'] = 'none'
            /* 设置水印相关属性end*/
            shadowRoot.appendChild(mask_div)
        }
    }

    // monitor 是否监控， true: 不可删除水印; false: 可删水印。
    const minotor = settings.monitor === undefined ? defaultSettings.monitor : settings.monitor
    if (minotor && hasObserver) {
        watermarkDom.observe(watermark_hook_element, option)
        watermarkDom.observe(document.getElementById(defaultSettings.watermark_id).shadowRoot, option)
    }
}

/* 移除水印*/
var removeMark = function() {
    /* 采用配置项替换默认值，作用类似jquery.extend*/
    if (arguments.length === 1 && typeof arguments[0] === 'object') {
        var src = arguments[0] || {}
        for (let key in src) {
            if (src[key] && defaultSettings[key] && src[key] === defaultSettings[key]) continue
            /* veronic: resolution of watermark_angle=0 not in force*/
            else if (src[key] || src[key] === 0) defaultSettings[key] = src[key]
        }
    }

    /* 移除水印*/
    var watermark_element = document.getElementById(defaultSettings.watermark_id)
    var _parentElement = watermark_element.parentNode
    _parentElement.removeChild(watermark_element)
    // :ambulance: remove()
    // minotor 这个配置有些冗余
    // 如果用 MutationObserver 来监听dom变化防止删除水印
    // remove() 方法里用 MutationObserver 的 disconnect() 解除监听即可
    watermarkDom.disconnect()
}

var globalSetting
/* 初始化水印，添加load和resize事件*/
watermark.init = function(settings) {
    globalSetting = settings
    loadMark(settings)
    window.addEventListener('onload', function() {
        loadMark(settings)
    })
    window.addEventListener('resize', function() {
        loadMark(settings)
    })
}

/* 手动加载水印*/
watermark.load = function(settings) {
    globalSetting = settings
    loadMark(settings)
}

/* 手动移除水印*/
watermark.remove = function() {
    forceRemove = true
    removeMark()
}

// 监听dom是否被移除或者改变属性的回调函数
var callback = function(records) {
    var watermark_parent_element = document.getElementById(
        defaultSettings.watermark_parent_node
    )
    var watermark_hook_element = watermark_parent_element || document.body
    var watermark_element = document.getElementById(
        defaultSettings.watermark_id
    )
    if (watermark_element === records[0].target || watermark_hook_element === records[0].target) {
        if (
            (globalSetting && records.length === 1) || (records.length === 1 && records[0].removedNodes.length >= 1)
        ) {
            loadMark(globalSetting)
            return
        }
    }

    // 监听父节点的尺寸是否发生了变化, 如果发生改变, 则进行重新绘制
    // var watermark_parent_element = document.getElementById(defaultSettings.watermark_parent_node)
    if (watermark_parent_element) {
        var newWidth = getComputedStyle(watermark_parent_element).getPropertyValue('width')
        var newHeight = getComputedStyle(watermark_parent_element).getPropertyValue('height')
        if (newWidth !== recordOldValue.width || newHeight !== recordOldValue.height) {
            recordOldValue.width = newWidth
            recordOldValue.height = newHeight
            loadMark(globalSetting)
        }
    }
}
watermarkDom = new MutationObserver(callback)
option = {
    childList: true,
    attributes: true,
    subtree: true,
    attributeFilter: ['style'],
    attributeOldValue: true
}
var recordOldValue = {
    width: 0,
    height: 0
}

export default watermark
